The present invention relates to a liquid crystal display, and particularly, to a structure of attaching and connecting a liquid crystal display unit which is configured so that, when connection terminals formed on a flexible circuit board are to be connected to a printed circuit board through a conductor-embedded elastic member, a corrugated elastic member is interposed between a holding member and the flexible circuit board, thereby enabling the attachment and the connection to be uniformly attached and conducted.
Conventionally, a conventional liquid crystal display unit is disclosed in, for example, Japanese Patent Publication (Kokai) No. HEI9-288278. As shown in FIGS. 4 and 5, in the conventional liquid crystal display device, a backlight 3 is placed on the back face of a liquid crystal display unit 1. The back light serves as a light guiding member 4 for guiding light emitted from a light emitting element 5 to illuminate the liquid crystal display unit 1 from the back side. A flexible circuit board 2 connected to the liquid crystal display unit 1 which is electrically connected to transparent electrodes via a conductive adhesive agent 7 is bent into a U-like shape. These components are fixed together by interposing members 6. Connection terminals 8 formed on the flexible circuit board 2 are drawn out to the back face and the outside of the back light 3 to be attached and connected to a connection member such as a connector which is not shown.
As describe above, the conventional liquid crystal display device is configured so that the back light 3 and the flexible circuit board 2 are fixed to each other by the interposing members 6. Therefore, a work of conducting this fixation is required, thereby producing a problem in that the production cost is increased. Furthermore, the connection terminals 8 formed on the flexible circuit board 2 are once drawn out to the outside and then attached and connected there to a connector or the like. This produces another problem in attachment and connection that the connection terminals 8 and the connector to be connected thereto must be prepared.
In order to solve the problems, it is an object of the invention to provide a display device comprises a holding member having a positioning boss and a hook for holding a liquid crystal display unit, a light guiding plate, and a flexible circuit board, a corrugated elastic member interposed between the holding member and the flexible circuit board; and connection terminals formed on the flexible circuit board attached and connected to a printed circuit board through a conductor-embedded elastic member, and which is therefore economical and has high connection reliability.
In order to solve the problems, a liquid crystal display device of the first aspect of the invention comprises: a liquid crystal display unit; a flexible circuit board which is connected to the liquid crystal display unit, contact portions being formed in a tip end portion of the flexible circuit board, the flexible circuit board being bent back outside a holding member described later; the holding member which holds the liquid crystal display unit; a printed circuit board to which the holding member is attached, and on which contact portions are exposed; conductor-embedded elastic members through which the contact portions on the printed circuit board are connected to the contact portions of the flexible circuit board, respectively; and a corrugated elastic member which is interposed between the holding member and the flexible circuit board to press the flexible circuit board, and the flexible circuit board is bent back outside the holding member and urged by the corrugated elastic member, whereby the printed circuit board is electrically connected to the flexible circuit board.
According to the first aspect of the invention, the corrugated elastic member is interposed between the holding member and the flexible circuit board to uniformly attach and connect the connection terminals formed on the flexible circuit board and the printed circuit board.
In the second aspect of the invention, a liquid crystal display device comprises: a holding member in which a positioning boss is erected from a back face, and which has a hook in a bottom portion; and a flexible circuit board which is electrically connected to transparent electrodes via a conductive adhesive agent, and in which, in a tip end portion that is bent into a substantially U-like shape, a positioning hole and contact portions are formed, the contact portions being connected to conductive elastic members described later; the holding member houses and holds, on a front side, a light guiding plate, and a liquid crystal display unit in which a liquid crystal composition is filled between a pair of substrates having transparent electrodes on inner faces, and, on a rear side, is fixed by passing the boss through the positioning hole, a main printed circuit board comprises a light emitting element, a positioning hole, and contact portions exposed on the printed circuit board, the liquid crystal display unit held by the holding member is attached and connected by: passing the positioning boss of the holding member through the positioning hole of the printed circuit board; engaging the hook with a predetermined position of the printed circuit board; and interposing a corrugated elastic member between a rear face of the holding member and the flexible circuit board, whereby contact portions disposed on the printed circuit board are connected to the contact portions disposed on the printed circuit board, through a conductor-embedded elastic members. Thus, the contact portions disposed on the printed circuit board are accurately connected to the contact portions disposed on the printed circuit board with adequate pressure.
In the third aspect of the invention, the corrugated elastic member which is interposed between the holding member and the flexible circuit board is configured evenly in a lateral direction across the boss, and the contact portions disposed on the flexible circuit board are arranged evenly in a lateral direction along a short side of the flexible circuit board. The invention has a function that the contact portions disposed on the printed circuit board, and those disposed on the flexible circuit board are correctly attached and connected in balance.
In the fourth aspect of the invention, the light emitting element disposed on the printed circuit board is housed in the holding member, and light emitted from the housed light emitting element is guided to the light guiding plate via a reflecting surface formed on the holding member. The invention has a function that light emitted from the light emitting element is guided to the light guiding plate via the reflecting surface formed on the holding member.
In the fifth aspect of the invention, the above mentioned liquid crystal display device is used in a portable telephone. Accordingly, when a liquid crystal display device is to be attached to a portable telephone, the contact portions disposed on the printed circuit board, and those disposed on the flexible circuit board are correctly attached and connected by an adequate pressure.